wallet: Implement `z_getnewaccount`

Closes zcash/zcash#5178.

qa/pull-tester/rpc-tests.py

@@ -64,6 +64,7 @@ BASE_SCRIPTS= [
     'p2p-fullblocktest.py',
     # vv Tests less than 30s vv
     'wallet_1941.py',
+    'wallet_accounts.py',
     'wallet_addresses.py',
     'wallet_anchorfork.py',
     'wallet_changeindicator.py',

qa/rpc-tests/wallet_accounts.py

@@ -0,0 +1,31 @@
+#!/usr/bin/env python3
+# Copyright (c) 2022 The Zcash developers
+# Distributed under the MIT software license, see the accompanying
+# file COPYING or https://www.opensource.org/licenses/mit-license.php .
+
+from test_framework.test_framework import BitcoinTestFramework
+from test_framework.util import (
+    assert_equal,
+    start_nodes,
+)
+
+# Test wallet accounts behaviour
+class WalletAccountsTest(BitcoinTestFramework):
+    def setup_nodes(self):
+        return start_nodes(self.num_nodes, self.options.tmpdir, [[
+            '-experimentalfeatures',
+            '-orchardwallet',
+        ]] * self.num_nodes)
+
+    def run_test(self):
+        # With a new wallet, the first account will be 0.
+        account0 = self.nodes[0].z_getnewaccount()
+        assert_equal(account0['account'], 0)
+
+        # The next account will be 1.
+        account1 = self.nodes[0].z_getnewaccount()
+        assert_equal(account1['account'], 1)
+
+
+if __name__ == '__main__':
+    WalletAccountsTest().main()

src/wallet/rpcwallet.cpp

@@ -16,6 +16,7 @@
 #include "proof_verifier.h"
 #include "rpc/server.h"
 #include "timedata.h"
+#include "tinyformat.h"
 #include "transaction_builder.h"
 #include "util.h"
 #include "util/match.h"
@@ -3016,18 +3017,15 @@ UniValue z_getnewaccount(const UniValue& params, bool fHelp)
     if (fHelp || params.size() > 0)
         throw runtime_error(
             "z_getnewaccount\n"
-            "\nPrepares and returns a new account, and its corresponding default address.\n"
+            "\nPrepares and returns a new account.\n"
             "\nAccounts are numbered starting from zero; this RPC method selects the next"
             "\navailable sequential account number within the UA-compatible HD seed phrase.\n"
-            "\nThe account will be prepared with spending keys for the best and second-best"
-            "\nshielded pools, and the transparent pool.\n"
             "\nEach new account is a separate group of funds within the wallet, and adds an"
-            "\nadditional performance cost to wallet scanning. If you want a new address"
-            "\nfor an existing account, use the z_getaddressforaccount RPC method.\n"
+            "\nadditional performance cost to wallet scanning.\n"
+            "\nUse the z_getaddressforaccount RPC method to obtain addresses for an account.\n"
             "\nResult:\n"
             "{\n"
             "  \"account\": n,       (numeric) the new account number\n"
-            "  \"unifiedaddress\"    (string) The default address for this account\n"
             "}\n"
             "\nExamples:\n"
             + HelpExampleCli("z_getnewaccount", "")
@@ -3037,10 +3035,17 @@ UniValue z_getnewaccount(const UniValue& params, bool fHelp)
     if (!fExperimentalOrchardWallet) {
         throw JSONRPCError(RPC_WALLET_ENCRYPTION_FAILED, "Error: the Orchard wallet experimental extensions are disabled.");
     }
-    int64_t account = 999999; // TODO placeholder
+
+    LOCK(pwalletMain->cs_wallet);
+
+    EnsureWalletIsUnlocked();
+
+    // Generate the new account.
+    auto skNew = pwalletMain->GenerateNewUnifiedSpendingKey();
+    const auto& account = skNew.second;
+
     UniValue result(UniValue::VOBJ);
-    result.pushKV("account", account);
-    result.pushKV("unifiedaddress", "TODO");
+    result.pushKV("account", (uint64_t)account);
     return result;
 }
 

src/wallet/walletdb.h

@@ -101,6 +101,7 @@ public:
     }
 
     void IncrementAccountCounter() {
+        // TODO: We should check for overflow somewhere and handle it.
         accountCounter += 1;
     }